The effects of oxygen dose on the formation of buried oxide silicon-on-insulator

Abstract

The effects of the oxygen dose on the microstructure and the dielectric properties of the buried oxide in oxygen implanted silicon-on-insulator (SOI) structures have been studied. Cross-sectional transmission electron microscopy analyses show that the density of oxygen precipitates at the silicon/buried-oxide interface increases with a decreasing oxygen dose when identical annealing processes are employed. Annealing studies reveal that 1275 °C anneals annihilate the oxygen precipitates. A longer annealing time is required to achieve an oxygen-precipitate-free silicon layer in an SOI substrate implanted with a lower oxygen dose. The inverse relationship between oxygen content in the silicon film and oxygen dose is attributed to the redistribution of oxygen during implantation. In the oxygen dose range studied, the thickness and the breakdown voltage of the buried oxide layer increase with increasing oxygen dose. Higher postimplant annealing temperature improves the isolation properties of the buried oxide layer.